Carb. Jetting using an A/F gage

[XR250]

I need to adjust the jetting on a new build for a 125cc Honda Navi. Started as 110cc and added a cam, pipe and carb and bore. I just installed an A/F gage on it.
If for example, it says I am at 11:1 at WOT, and am running a 110 Main jet, should I try a 11/12.5 x 110 = 98 (say 100) main jet assuming I want 12.5:1 as my target mixture?
Also, is 12.5 a good number for WOT? What should I be shooting for a low and mid throttle?


Thanks

 

[XR250]

There might be something found in tailoring the length of that runner to the operating RPM of the engine.

Maybe but not enough motivation here for that